Freddie Highmore’s latest patient brings back painful memories on The Good Doctor.

On Monday’s episode of ABC’s hit medical drama, Dr. Shaun Murphy (Highmore) encounters a young patient who looks eerily similar to his late brother, Steve.

In ET’s exclusive sneak peek, Shaun attempts to connect with the boy, who’s seen his fair share of hospitals in his young life. When the patient cracks a joke while waiting to be scanned, Shaun hesitates before doing his best to respond with a quip of his own, after seeing a hospital employee stifle her laughter.

“Tough to tell without looking at you, but I’m guessing that was sarcasm?” the boy says, slightly amused.

“No. I have autism, which makes it hard for me to read social cues. Jokes are difficult,” Shaun acknowledges.

When the boy reveals that he “used to know” a kid named Peter who also had autism, Shaun’s curiosity piques. That’s when he learns that Peter died after getting hit by a car, prompting memories of his late brother’s death to come flooding back.

“It’s appointment TV. People are watching it live with family members and in overwhelming numbers. I don’t think I could have imagined a better outcome, not just for pure ratings,” Gonzalez says. “We’re storytellers. We want to affect people. We want to tell other people’s stories that others might not here. I think that’s what this show does, not only with its diversity and dealing with characters that are outside of neuro-normative ideals. It’s just so much more than I could have hoped for the show.”